Grinding disk reconditioner



VIVHLY 4, 1954 M BACK 2,677,362

GRINDING DISK RECONDITIONER Filed Feb. 26. 1951 I" v" z 24 29 4/ P lNvEN-roR JAL/REL N. BncK BY ...71 g. 9 M7 ny'w ATTORNEY Patented May 4, 1954 meer UNITED STATES PATENT GFFICE GRINDING DISK RECONDITIONER Laurel M. Back, San Lorenzo, Calif.

Application February 26, 1951, Serial No. 212,800

4 Claims.

The invention relates to a hand-applied tool for dressing and cleaning the working surface of a rotary grinding disc or the like.

An object of the invention is to provide a tool of the class described having a rotary working head which is adapted to constantly present fully operative working points against an abradant face being treated.

Another object is to provide a tool of the class described having a working head comprising a series of axially spaced toothed disc cutters arranged to be independently rotated by a rotating disc for individually treating the engaged surface thereof.

A further object is to provide a rotary cutter head of the character described having means providing an adjustable frictional drag against a turning of its disc cutters during a working application of the head.

A more specific object is to provide a tool of the character described having its head arranged for its periodic reversed working applications to compensate for its wear and to maintain the full operativeness of the tool.

Yet another object is to provide a tool of the class described having its working head replaceably mounted on the handle of the tool in a particularly simple and effective manner.

The invention possesses other objects and features of advantage, some of which, with the foregoing, will be set forth or be apparent in the following description thereof, and in the accompanying drawings, in which,

Figure 1 is a view transverse to the working face of a grinding disc, and showing a present reconditioning tool operatively applied to it.

Figure 2 is a side elevation of the disc and the applied tool.

Figure 3 is an enlarged fragmentary section taken at the broken line 3-3 in Figure 1.

Figure 4 is a partly sectional elevation of a shaft element of the tool structure.

Figure 5 is an enlarged fragmentary, and partly sectional, view taken generally at the line 5-5 in Figure 2.

Figure 6 is an enlarged fragmentary view showing the working relations of successive teeth of a present head to an engaged treated surface.

Figures 7 and 8 and 9 progressively illustrate forms assumed by the working ends of the tool .5.a

teeth by reason of the wear thereof by an abrasive disc face being treated.

The working face of a grinding member generally comprises abrasive particles secured to and extending from a backing element, and may become effectively smooth with use by reason of a breaking or wearing away of the working points of its abradant particles and/or a clogging of the depressions between the particles with materials removed from workpieces by the Working face, said materials including metal filings or paints or sawdust, etc., which may adherently stock to the working surface of the grinding disc. Accordingly, the present tool II hasbeen particularly designed for reconditioning an abrasive working surface by a repointing fracturing of abradant particles which have been worn to present relatively smooth working faces and removing material which has become lodged on and between the particles, the tool being manually applied in a particularly eifective manner to restore a treated surface to its full working condition. Also, a present tool is eifectvely selfsharpening for its constant effectiveness as it is worn by abradant surfaces being treated.

For illustrating its use, a tool I I embodying my invention is shown as operatively` applied to the at working face I2 of a grinding disc I2 which is mounted on a backing member I3 comprising a fiat annulus I3 extending from a hub I3" which is threadedly mounted on the extremity of a driving arbor I4. As particularly shown, a screw cap I5 is threadedly mounted on the extremity of the arbor i4 extending through an axial opening I2" of the grinding disc I2 and is provided with a radial outer flange I5 for clamping an adjacent circular inner portion of the disc I2 against a complementary countersunk seat provided by the opposed face of the annulus I3 whereby the working face I2' of the disc extends radially outwardly from the flange I5. The arbor I4 carrying the grinding head assembly may be provided by either a stationary machine in which the disc is disposed in a fixed horizontal or vertical or angular plane or by a portable grinder which is arranged for working application over a flat surface and may be disposed with its working face I2 facing upwardly for a most convenient application of a present tool II.

It will now be noted that a tool II essentially comprises a cylindrical head assembly Il providing relatively rotatable elements carried on a tubular shaft I8 which is non-rotatably and removably mounted on a handle member I9 extending radially of the shaft axis, working elements 2l of said head assembly being rotatable by the engagement of working points thereof with a moving surface to be treated. The present working elements 2I are formed of sheet metal of uniform thickness and requisite hardness, comprise discs uniformly and radially slotted inwardly therearound to provide relatively long teeth 22 separated by generally sector-shaped slots 23 in a star wheel conformation, are axially perforated to rotatably receive the shaft I8, and have central hub portions 24 between their shaft-receiving holes and the bases of their teeth. Rings 25 are engaged in pairs as spacers between the hub 'portions 24 of the toothed discs 2| in their line on the shaft I8, a pair of like rings 2S is mounted on the shaft I8 outwardly of an element 2| at one end of their line, and a pair of rings 21 and 28 is provided opposite the element 2| at the other end of the line. 'I'he various spacing rings 25 are preferably of like size 'and thickness whereby the discs may be uniformly spaced along the shaft I8 and present like friction faces to each other and to the opposed 'dise hub, and the rings 2B and 21 and 28 are of like material and conformation.

As particularly illustrated, the aforesaid cutter Ielements 2| and the rings V25 and 26 and 2:1 and 281are1`secur'e'd on the -shaft I8 fbe'tween outtu'rned terminal flanges 2-9 'thereof whereby the discs 2| and the various washers are Yretained. on the shaft t8 to provide the :head assembly I1, it being understood that the'was'hers 25 between the toothed elements "21| function asspace'rs between -the Alatter elements, and that the end washer pairs function generally as 'spacers -between theshaft vflanges -29 and the adjacent elements v25|. 'The arrangement is essentially su'oh that mutually independent relative rotations Vof the spaced velements 25| are permitted upon the application of the teeth of `said elements against arotatingdisc :|22 while the-shaft axis is disposed generally vradially *of the disc, it being understood that points `of the r-working face I2' `of a grinding disc |52v-at increasing distances from its center move at lproportionally increasing circular-`sp`eeds as thedi'scislrotated.

Recalling that th`e-eutt'ersand the variousrlrigs of A the `head assembly -ar'e 'held on the -s'haft VI8 between -its en'd flanges "29 Ito permit =a yrelative rotation of 'the cutters iv2| by their individual-engagement with the working face I2ofa'grinding disc I2, rneansare *preferably provided fior frictionally 1and independently restraining -the 1cutters to peripheral 'rotative speeds which are slightly l'ess 'than that 3'of lthe grinding v"disc -at their line -of "tooth engagement therewith, 'this insuring-a more uniformapplication'of thewoking points lof the Acutter teeth of "their set. As particularly shown, 'the 'washer element 23 of 'the head I6 v'threadedly"mounts a plurality 'of screws 3| 'axially vthereof and having their Iheads disposed outwardlfylof said washer and lhaving their shank rextremities simultaneously -engiageable `in complementary sockets32 providedin the opposed face ofthe Washerl. -Since the Aelement y28 directly engages a shaft Lflange 29, 'and the lWasher element L26 at Ethe :other Aend of the 'assembly Il engages `'theother'end flange '29 of 'the shaft I8, a screwing-in of the screws 3| as thrust elements'agai'nst the' element 2`l arranged t'o clamp the remaining elements of `the assembly |'1 togethery to an adjusted idegree to provide a desired vdegree 'of resistance "to rotation 'of 'the toothed 'dises 2|. AZit will'be'understood that'the opposed washer anddisc'faces have the "same frictional properties, -vand that 'thepaired use bf the spacer Arings in'the assembly provides'for a more Luniform 'distribution 'of the frictional 'drag along the line of discs.

It will now be noted that the present handle I9 comprises a fiat and generally V-shaped element shaped of a single piece of round rod or heavy wire to provide like sides 34 extending from an open connecting return bend 35, and having end portions 36 thereof turned mutually inwardly at bends 3l for their simultaneous mounting engagement in the bore of the tubular shaft I8 from opposite ends thereof. The handle element is 4'preferably of somewhat `resilient material whereby the handle may be sprung open for mounting or dismounting the described uni* tary head assembly on and between the handle .portions 35. When the handle ends 36 are engaged in the tubular shaft I8 they may swing, or be' swung, toward each other to forcibly engage :the insides of the bend portions 3l with the ends of the shaft I8 for securing said shaft against rotation about said ends; preferably, and as shown, the end flanges 29 of the shaft mem ber I8 are 'provided with corresponding notches 2`9' rer-complementariiy receiving the bend portions of the handl'elsicles forrinsuring anon-rbtatifvesmeuntingiof the shaft onthe inturned .handle portions 36.

Means are preferably provided for non-rotatably rand releasably securing the vshaft I8 of -a head assembly on the handle I9. .iAs particularly shown, `'a rectangular plauze fm'ember `33 Shaving an interior rectangular handle-receiving :slot 38 across -it and equally spaced from 'parallel edges of 'the plate, is 'provided for mounting -on the handle fand 'its advancement iafl'ong the handle toward the shaft-mounting end thereof to Wedg'e'dlydrawthehandle:sides 32 together and effect 'a positive Sand lreleasable .gripping -of the head Il by the handle. Inlthe present structure, corresponding not'ches "34' are Vprovided Iat -mutually opposite points of the 'handlesides 34 for selectively receivingthe portions lof the 'plate 38 at the ends fof its slot 39 to secure the :plate in adjusted 'operative Eposition on the 'handle for effecting the required gripping engagement vof the shaft I8 by the handle, it being understood that the-release 'of the' installed plate 538 .may be efiected by-springing fthe ihandle sides toward each other 1Iintlfieir plane. :It will be noted that, by reason of the-'extensionof the lheads of lthe clutch fserews 3| Ifrom `lthe element 28, v4one 'of the screwelieads is Aarranged to engage vthe corresponding handle iside f3'4 at its Ib'en'd '3l "for securing rthe :clutch element f28 against rotation. Also, the Obliquity of the shaft-:end lflanges 29 providesfortheir wedged engagement within the bores'fof the 'elemeritllfandlthe:element '2G-at the other `end of *theassembly f|`| whereby these elements are ffurtherres'trained against their -rotation with the rest of the elements of the lhead assembly.

It will '-n'ow benoted that a present tool zI'I 'is arrangedfor :its vmanual 4working application against the working v'faceIZof arotating-grindingdisc f2 with the 'axis lo'f its headassembly extendinggenerallyradially of theaxis of rotation of the disc, and with its handle l'making a relatively 'small'anglewith the plane'of the-disc face |f2'. Starting with the 'head 'I7 applied with appropriate `pressure to the disc 'face I2 immedi'atelyadjacent the flange .15' vof the discsecuring member I5, the'headisswung'outwardly on -the 'disc -'face vI2 to `progressively operate 'on the same by reason 'ofthe engagement of .the moving disc facewith 'the toothed 'wheels 2l 'for radially operating across' the disc `face 'I2'.

the use of the present tol, experiencehas'shown' that it is best applied with the axis of rotation of its head slightly ahead of and parallel to a radius from the axis of rotation of thedisc, whereby the line of the handle i9 makes an angle of about four degrees with a radius intersecting the line of engagement of the head l1 with the disc while the latter is in its starting position. With the head applied against a grinding disc i2 in the particularly described location and manner, no tendency to hold the head inwardly'is noted as is the ease when the tool is applied.r on or rearwardly through a radial line from the rotative axis of the disc. The applied tool may be dragged under manually applied pressure across a disc face l2' or be applied by repeatedly striking it against said face as it is moved outwardly thereover.

In the use of a present tool Il in the indicated manner, it has been found that the end faces of the teeth 22 tend to wear at an angle to radial lines thereto, this effect being heightened by the described clutch-controlled drag which is imposed on the cutter discs 2|. As a result of the aforesaid circumferential bevelling wear on the tooth ends, a tooth tends to assume the form shown in Figures 6 and '7 and 9 in which the tooth end face lacks an operating point, but operates rather along a line having the circumferential width of the axially thin teeth, and termihating at an acute-angle rear point dl of the tooth. If, however, the formed acute-angle points il of the teeth 22 of a head l1 are subsequently applied in forward relation to the teeth (Fig. 7), the wear on the teeth ends resulting from a working application of the tool head will progressively wear back the points il! to provide obtuse-angled points 42 (Fig. 8) which travel across the tooth ends to finally become points 4| (Fig. 9).

Since a forwardly-disposed point 4l and a travelling point 42 are operative as narrow chisel points in the depressions of an abradant face l2', the action thereof is distinctly more effective than is a rearwardly disposed point 4| resulting from a sufficiently long application of the tool to a disc face i2. Accordingly, when the points 4l have been formed at the rear edges of the teeth 22 of a head I'I, the tool is preferably manipulated in a manner to present the formed points di forwardly for providing the described travelling point 42, the process being repeated for a continued best operative use of the tool. With the present structure which is symmetrical with respect to the plane of the handle, the forward disposal of a formed point 4I may be simply effected by rotating the tool through a half-turn of' the handle to reverse the operativeness of the teeth with respect to the working face I2. Alternatively, and particularly if the handle and head are not parts of a symmetrical structure, the head il may be reversely mounted on and between head-gripping handle members corresponding to the inturned ends 36 of the present handle. For

providing the described action, a present cutter wheel 2l desirably has sixteen teeth 22 of uniform width circumferentially of the wheel whereby their ends may remain of substantially con- ,etant length as a point 42 is progressively provided along them.

From the foregoing description taken in connection with the accompanying drawings, the advantages of the present grinding disc reconditioner will be readily understood by those skilled in the art to which the invention appertains. While I have described the principles of operation, together witha form of my invention which I nowconsider to comprise a preferred embodiment thereof, I desire to have it understood that the showing is primarily illustrative, and that such changes and developments may be made, when desired, as fall within the scope ofthe following claims.

4I claim: i1. In a tool for dressing flat abradant surfaces, a tubular shaft member providing cutturned flanges at its ends, a head assembly comprising disc cutters and spacing rings rotatably mounted upon the shaft member between its flanges, a planarl handle member of V-outline shaped of a length of wire or the like andhaving its sides tapering from mutually inturned ends engaged in the bore of the shaft member and cooperative with the flanges of the shaft member to secure the member against rotation relative to the handle, and a plate member providing an interior slot slidably receiving the handle transversely therethrough with the handle sides in frictional slidable engagement with the slot ends and with the plate movable along the handle toward the engaged shaft member to wedgedly for-ce the sides of the handle toward each other in their plane to effect a gripping of the engaged shaft flanges against a rotation of the shaft with respect to the handle.

2. In a tool for dressing ilat abradant surfaces, a shaft member providing outturned flanges at its ends, a plurality of like disc cutters providing circumferentially spaced teeth and rotatably mounted upon the shaft member between its flanges and arranged for mutually independent rotations thereof by reason of the application of the tooth ends to a moving work surface, spacing rings alternating with the disc cutters on the shaft member in frictional engagement therewith, end pairs of spacing rings engaged between the different flanges of the shaft member and the end cutters of their line, and thrust screws carried by a latter spacing ring and adjustable transversely of the ring and against the opposed spacing ring of its pair to effect an adjusted frictional engagement of the cutters and the spacing rings engaging them.

3. In a tool for dressing nat abradant surfaces, a shaft member providing outturned flanges at its ends, a plurality of like disc cutters providing circumferentially spaced teeth and rotatably mounted upon the shaft member between its flanges and arranged for mutually independent rotations thereof by reason of the application of the tooth ends to a moving work surface, pairs of spacing rings alternating with the disc cutters on the shaft member and including end pairs between the end cutters and the flanges having the outer rings thereof engaging the different flanges of the shaft member and the inner rings engaging mutually opposed cutters, and thrust screws directly coactive between the spacing rings of a said end pair transversely thereof to mutually and forcibly separate said rings for a mutual frictional engagement of the cutters and rings in their line.

4. In a tool for manual manipulation for cleaning and dressing abradant surfaces, a tubular shaft member, a head assembly comprising disc cutters and spacing rings rotatably mounted upon the shaft member between its ends, a planar handle member of V-outline shaped of a length of wire or the like and having its sides tapering from mutually inturned ends engaged in the bore of the shaft member, and a plate emmen member providing an interior slot fslidably receiv- Number Name Date ing the handle .transversely therethrough with 43,128 Hallgren Feb. 13, 1900 themutual-ly outer faces of the handle sides 'in 673,634 Butler May 7, 1901 frietonal engagement with .theslot ends whereby '1,575,637 Neth Mar. `9, 1926 the-plate ismovable along the handle toward the 5 i 1,589,208 'Mitchell June 15, 1926 handle-mountng shaft from the ysmaller handle 1,819,375 Matthews Aug. 18, 1931 end to force the sides of the handlefmember to 2,595,984 Saere May, 1952 ward each other in their plane to effect a nonrotative gripping Aof the engaged shaft :between FOREIGN PATENTS them. lo Number A Country Date 863,600 France .V Aug. 18, 1941 .References yCited in the le .of this patent UNITE-D STATES PATENTS Number Name Date 1 425,485 Bennett lmm- Apr. 15, 1890 5 

